Vault of the Warrior

The Vault of the Warrior is fairly straight forward. The only objective here is killing the Warrior and finishing the game. The only way to access this area is by traversing Hero's Pass. This vault is deep within Pandora and dug up by Hyperion. You'll find some Hyperion structures and then end up in the actual vault which is surrounded by lava and Eridian statues.

You will start on a path that only goes one way. Like most of the endgame locations, the vault is fairly linear and offers little to be explored. Anyway, this path will lead you to an elevator that everyone must be on before progressing.

Continuing a bit further, you'll notice two vending machines (health and ammo) and a fast travel node that only leads to the main locations.

The final area is the actual vault of the Warrior. It appears as an Eridian shrine with a hole in the ground set for the Vault Key. Once you step into this area, the Warrior will spawn automatically if you have already completed the campaign. There are a few rakk and crystalisk in this area but no other enemies. It's worth noting that there are a few machines in this area that you can use to spawn two crates that contain health and ammo. You can do this once every 99 seconds.

After finishing the Warrior off, the exit is at the south point of the vault which takes you back to Eridium Blight.